7-endo Selective Friedel–Crafts Cyclization of Vinylepoxide Compounds and 8-endo Selective Friedel–Crafts Cyclization by use of Acetylene Cobalt Complex

Abstract

Treatment of arylpropyl vinylepoxides linked to ester with BF₃•Et₂O in CH₂Cl₂ undertook stereospecific 7-endo selective Friedel–Crafts (FC) cyclization to give seven-membered ring products in excellent yields. Di- and tri-substituted epoxides were acceptable for this new reaction. We also developed 8-endo selective FC cyclization of vinylepoxides containing alkyn-dicobalt complex moiety to give eight-membered ring products in excellent yields.